Safety cut-off device for gas burners



Oct. 1l, 1932- A. LUNDIUS ET AL SAFETY CUT-OFF DEVICE FOR GAS BURNERS Filed May 31. 1930 0MM INVENToRs Patented Oct. 11, 1932 UNITED STATES PATENT@ OFFICE ALTON LUNDIUs, E JERSEY CITY, AND oTTo DIETRIcHsoN, 0E soU'rH ORANGE,

f NEW JERSEY SAFETY CUT-OFF DEVICE FOR GAS BURNERS Application Ied May 31, 1930. Serial No. 458,015.

This invention relates to safety cut-off devices for gas burners, particularly household cook-stove burners, and provides improve- `ment therein. y

There is a certain hazard connected with the use 'of gas burners. rllhey are not infrequently accidentally extinguished, as by gusts of wind, boiling over of contents of vessels, acts yof mischievous children, etc., and the escaping gas is extremely apt to result in loss i of life and property.

The present invention provides an improved device for cutting off the flow of gas when ythe ame is accidently extinguished. It

15. provides means comprising a thermostat l Y which acts relatively quickly, after eXtinguishment of the llame to eut-olf the flow of gas; the thermostat may begin to act as soon as cooling begins irrespective of the degree of `2Q; deflection of the thermostat by the heat. The

invention further provides avery simple,

effective and reliabledevice for the intended purpose.

Y An embodiment of the invention is illustrated in the accompanying drawing, where- Fig. 1 is a view in side elevation of. a cookstove gas burner, equipped witha safety cutoff means according to the present inven- Fig. 2 is a bottom plan view.`

Fig. 3 is anenlarged detail view showing the valve in vertical section and the other parts in vertical elevation.

Fig. 4 is a horizontal sectional view (enlarged) on line IV-IV, Fig. 2 through the clutch. t

vReferring to said drawing, numeral 10 illustrate's a gas-burner of conventional form.l 4o, comprising a plurality of radiating arms,

having numerous perforations through which the air and gas mixture which is burned, escapes. Gas enters the burner through a nozzle 12, and air through perforations- (not V45". Shown) in mixing chamber 14.

I Numeral 16 designates a cut-off valve controlling the flow of gas through nozzle k12. The usual manual valve 18 may be and preferably is arranged between the cutfoff valve .59.y 16 and a gas Supply pipe 20. l

Numeral 22 designates a thermostat located in position to be heated by the iame from burner 10. As shown, the thermostat may be attached at one end to a bracket 24 attached to one of the arms of burner 10. The thermostat is preferably a bimetal strip composed of two metals (or alloys) 25, 26, having different coetlicients of expansion.

Numeral designates suitable connecting means for transmitting'movements of the 60 thermostat 22 to the cut-off valve 16. The connecting means may comprise a rod 32 and a lever 34, the rod being connected at one end to the free end 36 of thermostat 22, and Y at its other end to one arm 38 of lever 34. 05 The cut-oftl valve 16 is preferably of the poppet type, the valve proper having a stem 40 projecting through the casing. An arm 42 of lever 34 is connected to stem 40, the Stem 40 being conveniently provided at its outer 70 end with a stirrup 44, into which a rounded portion of arm 42 lits. kA spring 46 may be and preferably is provided for normally pressing the valve-proper toward its seat 48.

A means is provided for opening cut- 75 olf valve 16 to admit gas to the burner 10 for starting a flame. i The means 5() is conveniently an arm or handle connected to lever 34 and adapted to rock the lever and thereby lift the stem 40 to open the valve. Arm 50 and 80 lever 34 may be connected by fastening both to a pin 52 which turns in a bracket 54.

A clutch is preferably provided in the connection 30. The clutch 60 iS preferably in the form of a sleeve 62, in which the rod 85 32 slides, and through which one end of the Said rod 32 projects as indicated at 64. The sleeve 62 is carried by a shouldered stud 66, which stud is pivotally connected toV arm 38 y of lever 34 as indicated at 68. The stud is 90 lightly held in position on the lever 34 by a cotter pin 70, or other Suitable means, and any interposed light spring 72. The lstud 66 and sleeve 62 are bored as indicated at 74, and a frictional connection is provided between the said sleeve 62 and rod 32 by means of a ball 7 8 or the like pressed against the rod 32 by means of a .spring 80. The friction provided by the spring 80 and ball 7 8 is made of sufficient amount that the resistance in the vent leakage' of gas'by. suitable means,tas a clutch 60 is slightly greater than the resistance of the spring 46 of the cut-od valve, whereby pull on the rod 32 may'act through the clutch lever to liftrthe valve proper against the closing'pressure of spring 46. The ends of sleeve 62 are preferably counterfbored, 'as indicated at 82, to prevent dirt accumulating on the rod from wedging between the rod and sleeve, and thereby in creasing lthe "frictional resista-nce of the clutch.

The arm or handle50 `may .be providedv with a tail-piece 83, adapted to make Contact with the end 64 of rod 32, and thereby force the thermostat 22 into a. deflected position, at the same time that Vthe cut-off valve 16 is opened to admit gas to the burner, in starting the burner. y

wiThe stem 40 passes through an opening 84 inthe valve casing, which is packed to preconvex leather washer 86, which fits clos-ely around the stem, and is pressed against the ToV produce a flame at the burner, the

normal kgas cock 18, which is ordinarilv a part of the combination, is lirst opened. The arm or handle` is then rocked to open the cut-off valve 16. The part 83 when used may'simultaneously force the thermostat 22 into adefiected position corresponding to a deflected position which it assumes when acted upon by the heat of the flame from the burner. The arm 50 being connected to the lever 34,' rocks the lever so that its end 42 lifts the valve stem'40 against the pressure ofthel spring 46, and hence admits gas to the nozzle 12,.which gas passes through the mixing chamber 14 tothe perforations in burner 10, whereupon it is ignited.

Where the arm or Vhandle 50 is provided with the tail-piece 83, thearm or handle 50 is held-momentarily after ignition of the gas to permit the heat to deflect the thermostat; otherwise no holding is necessary, as the clutch will slip on rod 32y and hold the cut-ofi'I valve lifted. The deflected ythermostat, pulling on the lever 34 through rod 132,

holds the valve proper lifted off'its seat as long as thermostat 22 continues to be heated by the burner flame.

, As the burner flame varies 1n intensity, the

thermostat 22 Vis deflected to` different dethat in the position to which the thermostat seat to enable the necessary amount of gas to pass `to maintain the flame With a greater intensity of flame, the thermostat 22 Vundergoes greater deflection. This greater defiection pulls upon therod 3 2,l and the clutch '60 allows the rod to slide forward in `the said sleeve 62. The deflection of the thermostat 22 by the -minimum flame also acts' Vthrough the connection 30 to press the shoulder 90 against seat 92, and thereby limit Y the movement of the lever 34, and alsopclose the opening in the casing around valve-stem 40, thereby amplifying the packingwasher' v86 in preventing escape of gas fromith'e cut` Voff valve casing .around the saidstem 40.',

Should they burner flame bel extinguished through any cause (as a draft, boilingover. of contents of cooking'. vessels, orthe-like), the thermostat 22 vwill quickly cool, and the thrust of the rod 32 will rockthelever 34, and seat the valve-proper, assisted by the spring 46. A. comparatively slight dropof temperature of the thermostat 22 on cooling,sufiicesV to move the cut-0H valve to closing position.'`

This drop lof temperature corresponds to the relativelysmall rise of temperature of the thermostat caused by theV heat of a'flame of minimum intensity, which acts, as heretofore described, to move the cut-'off valve to open position. After the cut-off valve has been closed by the initial movement of the thermo stat lon cooling, thepush on rod 32 occasioned by further cooling' ofthe thermostat pushes the said rod through the clutch l60, and the rod 32 continues to slide through the clutch (against the frictional resistance thereof against the rod 30), until the thermostat 22'k resumes its vnormal position corresponding to the temperature of the room. It will therefore be seen that the arrangement is such that a small rise in temperature, corresponding to the heat imparted to the thermostat by a minimumflame, sufhces to hold the cut-off valve 16 open, and that irrespective of the amount of deflection'l of the thermostat 22 by flames of any intensity above theminimum, that the thermostat, immediately 'upon extinguishment ofthe flame begins to act to close the cut-off valve, and effects closure upon cooling through a relatively small number of degrees, and'throughout the. remainder of its cooling the rod 32 connected thereto slips through the .clutch 60, exerting a force meanwhile through the lever 34 in a direction to maintain the cut-off valve closed.

The location of the armor handle 50 between the cut-olf valve 16 and the usual cock mischievously openzthe coc`k18, `and thereby provides a safeguard against a 'child mischievously playing with the gas burner.

The invention may receive various other embodiments than that herein specifically illustrated and described.

What is claimed is:

1. A safety cut-ofi' device for gas burners, comprising a` g'a's cut-off valve, a thermostat, and connections between said thermostat and cut-ofil valve, wherein said connections comprise a rod attached to said thermostat and a sleeve having a limited to and fr0 movement, said rod being slidable in said sleeve and said sleeve having a spring-pressed part therein adapted to bear on said rod and impositively grip the rod, whereby said rod may slide in said sleeve against the action of said spring-pressed part under the action of said thermostat after said sleeve reaches a limit of its movement, substantially as and for the purpose described.

2. A safety cut-off device for gas burners, comprising a gas cut-off valve, a thermostat, and connections between said thermostat and cut-olf valve, wherein said connections comprise a rod attached to said thermostat, a lever connected to said cut-off valve and having a limited arc of movement, and a sleeve having a swivel connection to an arm of said lever, said rod being slidable in said sleeve and said sleeve having a spring-pressed part therein adapted to bear on said rod and impositively grip the rod, whereby said rod may slide in said sleeve against the action of said springpressed part under the action of said .thermostat after said sleeve reaches a limit of its movement, substantially as and for the purpose described.

3. A safety cut-0E device according to claim l, wherein said sleeve has an enlarged internal diameter at its ends, which ends overhang the adjacent portions of the rod and prevent an accumulation of dirt on said portions of the rod and thereby inhibit sticking of the rod in the sleeve.

In witness whereof, we have hereunto signed our names.

ALTON LUNDIUS. OTTO DIETRICHSON. 

